Electronic systems commonly use Multi-Layer Ceramic Capacitors (MLCC) for such tasks as decoupling power supplies, or filtering signals. The ceramic material in the MLCC has a piezoelectric property which causes it to expand and contract in response to applied electric fields. This expansion and contraction can cause the components to vibrate. These components are very small, so the vibration of an individual part may not be significant. However, when there is an array of these parts vibrating synchronously, the effect is increased. Further, once the parts are fixed to a large, flexible substrate, as is the case when they are soldered down to a printed circuit board (PCB), the vibration is amplified further. What might have been a benign problem becomes a serious problem, particularly when the driving voltage varies at a frequency in the audible range. The problem may be manifested as a high pitched squealing noise coming from the product.
To combat this problem, system engineers and component engineers have focused on MLCC package modifications to minimize the coupling to the PCB, and on placement of the MLCCs, sometimes in pairs, to partially cancel or otherwise reduce the amplification of the vibration. Modifications to the package can lead to degraded performance of the capacitor when the mechanical changes add series impedance. Creative layout solutions only go so far in dampening the acoustic noise, and in many cases require compromises in electrical performance or space allocation to implement them.
Therefore, what is desired is a method or system to eliminate or greatly reduce acoustic noise in electronic systems caused by MLCC or other similar components containing piezoelectric material.